We are living in the "Age of Migration" and migration has a profound impact on all aspects of society and on religious institutions. While there is significant research on migration in the social sciences, little study has been done to understand the impact of migration on Christianity. This book investigates this important topic and the ramifications for Christian theology and ethics. It begins with anthropological and sociological perspectives on the mutual impact between migration and Christianity, followed by a re-reading of certain events in the Hebrew Scripture, the New Testament, and Church history to highlight the central role of migration in the formation of Israel and Christianity. Then follow attempts to reinterpret in the light of migration the basic Christian beliefs regarding God, Christ, and church. The next part studies how migration raises new issues for Christian ethics such as human dignity and human rights, state rights, social justice and solidarity, and ecological justice. The last part explores what is known as "Practical Theology" by examining the implications of migration for issues such as liturgy and worship, spirituality, architecture, and education.